Symbioses of Cyanobacteria in Marine Environments: Ecological Insights and Biotechnological Perspectives

Abstract

Cyanobacteria are a diversified phylum of nitrogen-fixing, photo-oxygenic bacteria able to colonize a wide array of environments. In addition to their fundamental role as diazotrophs, they produce a plethora of bioactive molecules, often as secondary metabolites, exhibiting various biological and ecological functions to be further investigated. Among all the identified species, cyanobacteria are capable to embrace symbiotic relationships in marine environments with organisms such as protozoans, macroalgae, seagrasses, and sponges, up to ascidians and other invertebrates. These symbioses have been demonstrated to dramatically change the cyanobacteria physiology, inducing the production of usually unexpressed bioactive molecules. Indeed, metabolic changes in cyanobacteria engaged in a symbiotic relationship are triggered by an exchange of infochemicals and activate silenced pathways. Drug discovery studies demonstrated that those molecules have interesting biotechnological perspectives. In this review, we explore the cyanobacterial symbioses in marine environments, considering them not only as diazotrophs but taking into consideration exchanges of infochemicals as well and emphasizing both the chemical ecology of relationship and the candidate biotechnological value for pharmaceutical and nutraceutical applications.

Anabaenopeptins: What We Know So Far

“…In addition to interaction with other cyanobacteria, these microorganisms are capable to establish symbiotic associations with invertebrates, such as corals, mollusks, and sponges. Both organisms can be benefited during this consortium through secondary metabolite production, for example [ 102 ]. Sponges host an enormous quantity of microorganisms belonging to diverse phyla, where cyanobacteria are mainly represented by genera Aphanocapsa , Synechocystis , Phormidium , and Oscillatoria [ 103 ].…”

Multiple bacterial partners in symbiosis with the nudibranch mollusk Rostanga alisae

“…Moreover, the protection of the enzyme nitrogenase that catalyzes N 2 fixation against oxygen is an important physiological requirement in bacteria such as symbiotic Bradyrhizobium , Burkholderia , Achromobacter , and Stenotrophomonas that are located in bacteriocytes and provide this protection. Synechococcus is known as a nitrogen-fixer 37 , 49 . It performs N 2 fixation in heterocysts where nitrogenase is restricted under oxic conditions.…”

Time after time: detecting annual patterns in stream bacterial biofilm communities

“…Environmental disturbances, for instance, elevated temperature, high light and eutrophic conditions (Olapade and Leff, 2005; Simonin et al ., 2019; Zhu et al ., 2019) provide ample opportunities that can be easily and competitively utilized by opportunistic bacterial taxa, including bloom‐forming bacterial communities (Piehler et al ., 2009). Research shows that cyanobacteria interact with their biotic environment in various ways, from impacting predator–prey interactions to forming mutualistic relationships with micro, macroalgae and non‐photosynthetic protists (Bauer and Forchhammer, 2021; Ma et al ., 2017; Mutalipassi et al ., 2021; Usher et al ., 2007). Cyanobacteria and proteobacteria coexist in >90% of bloom‐forming bacterial communities, contributing equally to the overwhelming majority of functional genes detected during bloom formation (Steffen et al ., 2012).…”